The Thompsons added Hewlett later claimed he had been to Morocco to sell something, but refused to elaborate further than admitting it had been "a good business trip and he made a profit."

When the couple contacted him in 2009 to ask about Madeleine's disappearance and his trip he replied sarcastically: "Yes, so? That makes me guilty then? In Morocco, everything's worth something. You can get 23 euros for an old bike."

There have been numerous reported sightings of Madeleine in the north African country. In 2007 photos of a blonde child being carried in a sling by a woman in Morocco prompted excited speculation she had been found.

Convicted paedophile Raymond Hewlett died of throat cancer in 2010

It quickly emerged the little girl - named Bushra Binhisa - was the daughter of an olive farmer of Berber extraction.

In July a British woman spotted a youngster “bearing a remarkable likeness to Madeleine” at a market in the northern Indian town of Leh.

There have also been reported sightings in Portugal, Belgium and France, but none have produced any firm leads.

The Mirror also quotes Peter Verran, 46, who also stayed on the same campsite as Hewlett between June and November 2007.

He said: "[Hewlett] told me gypsies wanted to pay good money for his daughter and he'd met some who traded in children and sold them to paedophiles."

A Scotland Yard spokesman told the paper: "We are not prepared to discuss any particular lines of enquiry."